mirror of
https://github.com/qmk/qmk_firmware.git
synced 2024-11-30 23:15:51 +00:00
154 lines
6.0 KiB
Plaintext
154 lines
6.0 KiB
Plaintext
Internal of HHKB pro
|
|
=====================
|
|
HHKB pro has MCU and some chips on separate two PCBs.
|
|
|
|
Controller PCB
|
|
--------------
|
|
M38K07M4 Renesas MCU with USB function
|
|
http://documentation.renesas.com/eng/products/mpumcu/rej03b0192_38k0ds.pdf
|
|
|
|
(HHKB_controller.jpg)
|
|
|
|
Keyswitch PCB
|
|
-------------
|
|
HC4051 Analog Multiplexer: select a row line.
|
|
http://www.alldatasheet.com/datasheet-pdf/pdf/203989/KODENSHI/KK74HC4051A.html
|
|
LS145 BCD Decoder: select a column line.
|
|
http://www.alldatasheet.com/datasheet-pdf/pdf/27373/TI/SN74LS145D.html
|
|
BU9831 Non-volatile electronic potentiometer: for calibration?
|
|
http://www.alldatasheet.com/datasheet-pdf/pdf/36387/ROHM/BU9831.html
|
|
TP1683/4 Capacitive Sensing controller: no datasheet available.
|
|
|
|
(HHKB_keyswitch.jpg)
|
|
|
|
Topre original chip?
|
|
(HHKB_TP1684.jpg)
|
|
|
|
|
|
Connector Cable
|
|
---------------
|
|
Two PCBs are connected by 15 lines(13 in case of Pro2).
|
|
Vcc and GND use 3(2) lines each, other 9 lines are for keyboard signaling.
|
|
|
|
Keyswitch connector
|
|
pro pro2 Description Teensy++ pins
|
|
--------------------------------------------------------------------------------------------
|
|
1 Vcc(5V) Not exist on Pro2 5V
|
|
2 1 Vcc(5V) 5V
|
|
3 2 Vcc(5V) 5V
|
|
4 3 TP1684 KEY: Low(0) when key pressed PE6 input(with pullup)
|
|
5 4 TP1684 KEY_PREV: make threshold PE7 output
|
|
6 5 HC4051 A(bit0)\ PB0 output
|
|
7 6 HC4051 B(bit1) > select row(0 to 7) PB1 output
|
|
8 7 HC4051 C(bit2)/ PB2 output
|
|
9 8 LS145 A(bit0)\ PB3 output
|
|
10 9 LS145 B(bit1) > select column(0 to 7) PB4 output
|
|
11 10 LS145 C(bit2)/ PB5 output
|
|
12 11 LS145 D(enable) Low(0) enables selected column PB6 output
|
|
13 12 GND GND
|
|
14 13 GND GND
|
|
15 GND Not exist on Pro2 GND
|
|
|
|
NOTE: guessing pin5(KEY_PREV) may work for hysteresis of capacitive sensing.
|
|
NOTE: 1KOhm didn't work as pullup resistor on KEY. AVR internal pullup or 10KOhm resistor was OK.
|
|
|
|
(HHKB_connector.jpg)
|
|
|
|
|
|
Keyswitch matrix
|
|
----------------
|
|
60 keyswitches in 8*8 matrix. It is ghost-free and bounce-free.
|
|
|
|
COL 0 1 2 3 4 5 6 7
|
|
ROW ---------------------------------------------------------------
|
|
0| 2 q w s a z x c
|
|
1| 3 4 r e d f v b
|
|
2| 5 6 y t g h n _NONE_
|
|
3| 1 Esc Tab Control LShift LAlt LMeta Space
|
|
4| 7 8 u i k j m _NONE_
|
|
5| \ ` Delete Return Fn RShift RAlt RMeta
|
|
6| 9 0 o p ; l , _NONE_
|
|
7| - + ] [ ' / . _NONE_
|
|
|
|
|
|
Matrix diagram:
|
|
|
|
+-------------------------+-+-+-+-+-+-+-+ Vcc
|
|
|bias control? - - - - - - - - ---
|
|
| 3.9K*8 R R R R R R R R |
|
|
+--------^+ +--------+ - - - - - - - - |
|
|
| 2| | HC4051 <0-------|-|-|-|-|-|-|-|--|R|-+
|
|
| |capa. | <1-------|-|-|-|-|-|-|-|--|R|-+
|
|
| TP1684 |sense | <2-------|-|-|-|-|-|-|-|--|R|-+
|
|
| 11<------| <3-------|-|-|-|-|-|-|-|--|R|-+
|
|
| | | <4-------|-|-|-|-|-|-|-|--|R|-+
|
|
| | | <5-------|-|-|-|-|-|-|-|--|R|-+
|
|
| <-+ | <6-------|-|-|-|-|-|-|-|--|R|-+
|
|
| 1 4 | | | <7-------|-|-|-|-|-|-|-|--|R|-+
|
|
+---V---^-+ | +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
|
|
KEY PREV | A B C +-----------------+
|
|
| | +-^----+ | | | | LS145 |
|
|
Vcc | | |BU9831| | | | +-^--^--^--^------+
|
|
--- | | +------+ | | | A B C D +------+
|
|
| | | | | | | | | | | |
|
|
1-3 4 5 6 7 8 9 10 11 12 13-15 |
|
|
+--------------------------------------------------+ |
|
|
| connector | ---
|
|
+--------------------------------------------------+ GND
|
|
to controller
|
|
|
|
|
|
Signals charts
|
|
--------------
|
|
While pressing space bar, watched HHKB original controller signals by logic analyzer.
|
|
Row and column is looping between 0-7 each for selecting a key.
|
|
A key is scaned every about 15ms, so scan rate is 66Hz.
|
|
|
|
(HHKB_chart1.jpg)
|
|
|
|
Space bar locate at ROW:3 COL:7. A key is selected by HC4051(C,B,A) and LS145(C,B,A).
|
|
Key state can be read on TP1684(4/KEY) while asserting low on LS145(D).
|
|
|
|
Usage of TP1684(5) is not clear. Controller seemed to output previous key state on this line.
|
|
However key state can be read without using this signal.
|
|
|
|
(HHKB_chart2.jpg)
|
|
|
|
|
|
Matrix scan pseudo code
|
|
-----------------------
|
|
for (row: 0-7) {
|
|
SELECT_ROW(row); // set HC4051(A,B,C)
|
|
|
|
for (col: 0-7) {
|
|
SELECT_COL(col); // set LS145(A,B,C)
|
|
|
|
_delay_us(40);
|
|
|
|
if (prev_key_state(row, col)) {
|
|
KEY_PREV_ON;
|
|
}
|
|
|
|
_delay_us(7);
|
|
|
|
ENALBLE_COL(); // set LS145(D) to low
|
|
|
|
_delay_us(10);
|
|
|
|
if (KEY == 0) { // read TP1684(KEY)
|
|
// key pressed
|
|
} else {
|
|
// not pressed
|
|
}
|
|
|
|
KEY_PREV_OFF;
|
|
UNALBLE_COL(); // set LS145(D) to high
|
|
|
|
_delay_us(150);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
EOF
|